The present disclosure relates to a transfer device that is suitable for application to a vehicle such as an automobile, and in particular to a transfer device to which a vane pump is applied as an oil pump that generates a hydraulic pressure of working oil or lubricating oil to be supplied to a transfer mechanism.
There has hitherto been utilized an oil pump as a device that generates a hydraulic pressure of working oil, lubricating oil, or the like (hereinafter referred to simply as “oil”) in an automatic transmission for a vehicle, for example. Among others, vane pumps that are unlikely to generate vibration and that are relatively small in size have been widely prevalent. For example, there is known a hydraulic supply device that includes a balanced vane pump (hereinafter referred to simply as a “vane pump”) as a hydraulic supply device that supplies a hydraulic pressure to a hydraulic device such as a valve body of the automatic transmission. An example of such a vane pump includes a first discharge port and a second discharge port, with the first discharge port communicating with the hydraulic device via a switching valve and with the second discharge port communicating with the hydraulic device not via a switching valve (see Japanese Patent Application Publication No. 2010-14101).
The vane pump is provided with a suction oil path that communicates with a strainer through which oil stored in a tank is suctioned. The suction oil path is merged with a return passage that leads oil discharged from the hydraulic device. This allows the vane pump to suction an extra hydraulic pressure from the hydraulic device, and increases the suctioned hydraulic pressure compared to a case where oil is suctioned through only the strainer. Thus, occurrence of cavitation can be suppressed.
In the hydraulic supply device described in Japanese Patent Application Publication No. 2010-14101, however, the suction oil path of the vane pump and the return oil path are merged with each other outside the vane pump. Thus, it is difficult that the suction oil path and the return oil path communicate with the vane pump after being merged with each other depending on the positions of installation of the strainer, the hydraulic device, and the vane pump, which may lower the degree of freedom in design.
An exemplary aspect of the present disclosure provides a transfer device in which a strainer and a hydraulic device can be disposed on opposite sides of a balanced vane pump at the center while suppressing occurrence of cavitation.
The present disclosure provides a transfer device including: a case that houses a transfer mechanism; a strainer that suctions oil stored in a lower portion of the case; a valve body that has a hydraulic supply circuit that supplies a hydraulic pressure to the transfer mechanism and a suction oil path that discharges an extra hydraulic pressure that is extra for the hydraulic supply circuit; a first suction inlet that communicates with one of the suction oil path and the strainer and a second suction inlet that communicates with the other of the suction oil path and the strainer; and a balanced vane pump that has a first suction port which faces the first suction inlet and into which oil flows from the first suction inlet, a second suction port which faces the second suction inlet and into which oil flows from the second suction inlet, a first discharge outlet and a second discharge outlet that discharge oil having flowed thereinto from the first suction inlet and the second suction inlet to the hydraulic supply circuit, and a communication oil path disposed downstream of the first suction port and downstream of the second suction port to communicate between the first suction port and the second suction port.
In the transfer device, the first suction inlet of the vane pump communicates with the suction oil path, and the second suction inlet communicates with the strainer. Thus, oil paths can be disposed without being merged with each other in the case where the valve body is disposed on the opposite side of the vane pump from the strainer. Consequently, it is possible to improve the degree of freedom in design. In addition, a flow rate from the suction oil path and the strainer is supplied to the first and second suction ports through the communication oil path. Thus, not only oil from the strainer but also an extra hydraulic pressure from the valve body can be suctioned. Therefore, the hydraulic pressure of oil being suctioned is increased compared to a case where only oil from the strainer is suctioned. Thus, it is possible to suppress occurrence of cavitation during low-speed rotation and high-speed rotation of the vane pump.